(a) Field of the Invention
The present invention relates to a fuel cell stack diagnostic system and a diagnostic method thereof, and more particularly, to a fuel cell stack diagnostic system and method thereof which more accurately determines whether a damage signal indicates a damaged unit cell.
(b) Description of the Related Art
A fuel cell vehicle generally uses a fuel cell stack and a high voltage battery to drive a motor. For example, when a vehicle is traveling uphill, electric power from both the fuel cell stack and the high voltage battery may be used to drive the motor. When a vehicle is traveling on a substantially straight road having no incline, electric power from the fuel cell stack may be used to drive the motor and the high voltage battery may be charged. When a vehicle is traveling downhill, the high voltage battery may be charged by regenerative braking energy produced by the motor, and electric power from the fuel cell stack is generated minimally.
Additionally, each unit cell of the fuel cell stack may be monitored using a stack voltage monitor (SVM) to determine whether each unit cell functions normally (e.g., without error). However, when the SVM fails or malfunctions, a diagnostic analyzer may misdiagnose a unit cell of the fuel cell stack as damaged and produce a damage signal. The diagnostic analyzer may be a fuel cell control unit (FCU). Therefore, a fuel cell stack diagnostic system and a diagnostic method thereof, which more accurately determine whether the damage signal from the diagnostic analyzer indicates that there is a real damaged unit cell or is merely a sensing error of the SVM, are required.
The above information disclosed in this section is merely for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.